Speeding a video by 5x and triming it
First of all, I can really recommend mikeycalmeyers videos on youtube. He has a whole series exlaining how to do video editing with Blender.

To answer your question, there are multiple ways to trim:

Option 1) Select your video and audio by holding shift and right clicking on them. Then put the green marker at the moment in time where you want to make a cut. From the menu just below your video sequence editor (the one with the tracks) choose Strip &gt; Cut (soft) at frame, or press the shortcut key K. This will split it into separate parts, so you can delete the parts you want to remove.

Option 2) Select the arrows on the left side of both your video and audio tracks by holding down shift and right clicking them. Then you can move them by pressing G and moving your mouse. For precise control use your arrow keys. When you moved it to the right location press enter.

To speed up your video:
Select (only) your video track with a right click. Then go to the menu in the video sequence editor and choose Add &gt; Effect strip &gt; Speed Control. Then on the right side uncheck Stretch to input strip length, set speed factor to 1 and multiply speed to 5 (or any other speed you like). You will need to drag the arrow on the right side of your original video track (so not the speed control) to match the new duration of your video track. Changing the speed of audio does not work this way, so I would use Audacity to change the speed and then import it into Blender.